Britain says it is seeking an explanation from the Nigerian government on the circumstances of the arrest of Nnamdi Kanu, who leads a banned group seeking a breakaway state in south-eastern Nigeria.

Mr Kanu,53, holds British and Nigerian citizenship. He faces treason-related charges in Nigeria, but fled the country in 2017 while on bail.

He was re-arrested on Sunday, according to the Nigerian government, but no details were given of where and how he was captured.

The British High Commission in Nigeria told the BBC that it was seeking clarification on the ‘’possible legality’’ of Mr Kanu’s arrest.

It said it was ready to give him "consular assistance".

A spokesperson, Dean Hurlock, said Mr Kanu was neither arrested in the UK nor extradited from there.

He said the UK expects his trial to follow due process.

Mr Kanu is currently in the custody of Nigeria’s secret police after a Federal High Court ordered for his detention on Tuesday.

His trial is expected to resume on 26 July.